Bilateral blood pressure differential as a clinical marker for acute aortic dissection in the emergency department
Bibliographic record
Abstract
INTRODUCTION: Interarm systolic BP differential is a classic sign of acute aortic dissection (AAD). All previous studies looking at the association of BP differential with AAD combine systolic BP differential >20 mm Hg with pulse deficit. Our aim was to assess the association of systolic BP differential with AAD, and its role in predicting AAD in the context of other signs and symptoms. METHODS: Historical matched case-control study using patient data collected between 2002 and 2014: participants were adults >18 years old with a bilateral BP measurement presenting to two tertiary care EDs or one regional cardiac referral centre in Canada. Cases were patients with diagnosed AAD; controls were those with a triage diagnosis of truncal pain (<14 days) and an absence of a clear diagnosis on basic investigation. Cases and controls were matched in a 1:1 ratio by sex and age. Bilateral BP differential and pulse deficit were compared between groups. RESULTS: A total of 222 patients (111 cases and 111 controls) were analysed. On univariate analysis systolic BP differential >20 mm Hg (OR 2.7, 95% CI 1.39 to 5.25) was significantly associated with AAD. Pulse deficit (diagnostic OR (DOR) 28.9) in isolation had better diagnostic accuracy than systolic BP differential >20 mm Hg in isolation (DOR 2.71) or combined with systolic BP differential >20 mm Hg (DOR 4.2). CONCLUSION: Bilateral systolic BP differentials >20 mm Hg are associated with non-traumatic AAD. However, the poor diagnostic accuracy and potential variability in measurement limits its clinical usefulness.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".